Zyngais announcing a new partnership with leading Chinese internet media conglomerate Tencent starting today. The two companies are kicking things off with a heavily localized version of CityVille built for Chinese audiences, that runs on Tencent’s developer platform.

Although Zynga has launched versions of FarmVille and Texas HoldEm Poker in Chinese already, this is the first time that we know of where the company has launched a game on a Chinese social platform. The other games had been built for Facebook, which is banned in mainland China, so they were only playable in Hong Kong, Taiwan and other parts of the world.

The timing of this launch and partnership may be a coincidence, but Zynga is about to go public, and one of investors’ favorite places to put money lately besides internet companies has in China. Along with the success of Empires & Allies in recent months, and its growth on mobile, the company is no doubt hoping this game becomes another example of how it can continue to make hits both on and off Facebook.

Like the Chinese language version of FarmVille before it, Zynga City isn’t just a translated version of the original game. Instead, it’s heavily adapted to local tastes — an effort led by Zynga China. With a name like “Zynga City,” the developer is smartly promoting the overall brand, which should help it launch other games in China down the road. Here’s a statement from the company with a little more color about what the new game will look like:

Zynga City beta will include brand-new decorations and architecture the Chinese audience can identify and connect with, in-game events and competitions linked to Chinese holidays and news, as well as culturally relevant game mechanics such as the chance for players to send street peddlers to their friend’s cities. Zynga City beta will also feature an innovative quest system to quench Chinese players’ thirst for rich storytelling within the games they love to play.

The title will launch Tencent’s Open Platform service, which is an integration of five platforms — Pengyou, Tencent Microblog, QQ Games, Q-Zone and Q+ –arriving on Pengyou first and then migrating to Q-Zone, the larger network, at a later date. Tencent Open Platform is meant to be a cross-platform solution for developers that offers everything from cloud data services and technical support to “self-help” advertisement, and in the press release, Tencent expresses the hope that the launch will increase interest among other third-party developers.

The original CityVille game continues to decline in monthly active and daily active users since its record-setting launch late last year. As of today, it’s down 9% in MAU to 80 million and down more than 15% in DAU to 14 million in the last 30 days, over the previous 30, according to our AppData tracking service. A standalone mobile version of the game called CityVille Hometown launched in late June and is currently hovering in the 40 to 30 range of top grossing iOS apps. Overall, it’s still Zynga’s largest game franchise at more than twice the size of the recently-launched Empires & Allies.

Other social developers who got big on Facebook have also been active on Chinese social networks, notably RockYou through its Asia studio. However, much of the Facebook gaming action in the country comes from local developers and studios building games for the platform. The Chinese government takes a heavy hand with internet content within its own borders, requiring social networks and developers to self-censor and maintain open lines with state censors in order to prevent pornography, pro-democracy speech and other illegal content from being shared among users. While Facebook and other tech companies haven’t yet figured out how to deal with this interference, companies like Zynga are presumably relying on their platform partners to ensure they don’t also find themselves having problems doing business in the country.